Step 2. Power off your device, Press the Volume up key and the Power button at the exact same time, wait until the phone screen wakes, it will enter into the device recovery mode. (You can also boot into stock recovery mode by Going into Settings Option> System Updates > Tap on the dotted button at the top and click on “Reboot into recovery”)

Step 3. Finally, click on “Updates system” & select the downloaded zip file. Wait for the upgrade is complete, reboot into the system.